ListBranchCommand.java

/*
 * Copyright (C) 2010, Mathias Kinzler <mathias.kinzler@sap.com>
 * Copyright (C) 2010, Chris Aniszczyk <caniszczyk@gmail.com>
 * Copyright (C) 2014, Robin Stocker <robin@nibor.org> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.api;

import static org.eclipse.jgit.lib.Constants.HEAD;
import static org.eclipse.jgit.lib.Constants.R_HEADS;
import static org.eclipse.jgit.lib.Constants.R_REMOTES;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.api.errors.RefNotFoundException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.revwalk.RevWalkUtils;

/**
 * Used to obtain a list of branches.
 * <p>
 * In case HEAD is detached (it points directly to a commit), it is also
 * returned in the results.
 *
 * @see <a
 *      href="http://www.kernel.org/pub/software/scm/git/docs/git-branch.html"
 *      >Git documentation about Branch</a>
 */
public class ListBranchCommand extends GitCommand<List<Ref>> {
    private ListMode listMode;

    private String containsCommitish;

    /**
     * The modes available for listing branches (corresponding to the -r and -a
     * options)
     */
    public enum ListMode {
        /**
         * Corresponds to the -a option (all branches)
         */
        ALL,
        /**
         * Corresponds to the -r option (remote branches only)
         */
        REMOTE;
    }

    /**
     * Constructor for ListBranchCommand.
     *
     * @param repo
     *            a {@link org.eclipse.jgit.lib.Repository} object.
     */
    protected ListBranchCommand(Repository repo) {
        super(repo);
    }

    /** {@inheritDoc} */
    @Override
    public List<Ref> call() throws GitAPIException {
        checkCallable();
        List<Ref> resultRefs;
        try {
            Collection<Ref> refs = new ArrayList<>();

            // Also return HEAD if it's detached
            Ref head = repo.exactRef(HEAD);
            if (head != null && head.getLeaf().getName().equals(HEAD)) {
                refs.add(head);
            }

            if (listMode == null) {
                refs.addAll(repo.getRefDatabase().getRefsByPrefix(R_HEADS));
            } else if (listMode == ListMode.REMOTE) {
                refs.addAll(repo.getRefDatabase().getRefsByPrefix(R_REMOTES));
            } else {
                refs.addAll(repo.getRefDatabase().getRefsByPrefix(R_HEADS,
                        R_REMOTES));
            }
            resultRefs = new ArrayList<>(filterRefs(refs));
        } catch (IOException e) {
            throw new JGitInternalException(e.getMessage(), e);
        }

        Collections.sort(resultRefs,
                (Ref o1, Ref o2) -> o1.getName().compareTo(o2.getName()));
        setCallable(false);
        return resultRefs;
    }

    private Collection<Ref> filterRefs(Collection<Ref> refs)
            throws RefNotFoundException, IOException {
        if (containsCommitish == null)
            return refs;

        try (RevWalk walk = new RevWalk(repo)) {
            ObjectId resolved = repo.resolve(containsCommitish);
            if (resolved == null)
                throw new RefNotFoundException(MessageFormat.format(
                        JGitText.get().refNotResolved, containsCommitish));

            RevCommit containsCommit = walk.parseCommit(resolved);
            return RevWalkUtils.findBranchesReachableFrom(containsCommit, walk,
                    refs);
        }
    }

    /**
     * Set the list mode
     *
     * @param listMode
     *            optional: corresponds to the -r/-a options; by default, only
     *            local branches will be listed
     * @return this instance
     */
    public ListBranchCommand setListMode(ListMode listMode) {
        checkCallable();
        this.listMode = listMode;
        return this;
    }

    /**
     * If this is set, only the branches that contain the specified commit-ish
     * as an ancestor are returned.
     *
     * @param containsCommitish
     *            a commit ID or ref name
     * @return this instance
     * @since 3.4
     */
    public ListBranchCommand setContains(String containsCommitish) {
        checkCallable();
        this.containsCommitish = containsCommitish;
        return this;
    }
}